Dynamo-electric machine.



No. 8.49,718. w IIPATENTED APR. 9. 1907. B. F. W. ALEXANDERSON. DYNAMO ELECTRIC MACHINE APPLICATION FILED JUNE 29,1905

WNW/asses @mim Err? g/M 4%. f/qzm @W;

' cord ance plying to til i) ERNST F. WV. ALQXANDERSON, OF

srrns arssr carton SCHENECTADY, NEW

YORK, ASSIGNOR A CORPORATION OF NEW YORK.

DYNAWlO-ELECTRIC MACHINE.

Specification of Letters Patent.

Patented April 9, 1907.

Application filed lune 29, 1905. Serial No. 267,509.

To all 11/71 01) it man concern Be it known that I, Enxs'r F. W. ALEXAN- DERSON, a subject of the King of Norway and Sweden, residing at of Schenectady, State of New York, have invented. certain. new and useful .lmpr'ove ments in Dynamo -Elcctric Machines, of which the following is a specification.

My invention relates t0 -'dynamo-electric machines, and is particularly applicable to self cxciting altcrnators of the type described in Patent No. 789,476, issued to me May 9, 1905. In that patent I disclosed a self-exciting alternatingcurrent machine comprising a ficld windtng provided with a rectifying-commutator and means for supthc fieldavinding through toe com mutator superposed voltages derived from the armature-winding in shunt andin series, respectively. A convenient method of 01 taining the shunt excitation is through an auxiliary winding carried by the arn'iature, and by means of this arrangement the ex pense of shunt-trailsformcrs is saved.

My presentinvention comprises a novel arrangement of the auxiliary Winding, and consists in forming it of conducting-strips placed-between the main armature-coils and the retaining-Wedges therefor.

My invention further comprises slotting the inner side of the retaining-wedges in or der to hold the conducting-strips securely in place.

Placing the auxiliary winding at the top of the slot directly beneath the wedges and above the mainwinding gives it'the most favorable position as While this arrangement does not increase the size of the machine.

My invention will best be understood by reference to the accompanying drawings, in Which- Figure 1 shows a small section oflthe armature of a dynammelcctiic machineprovided with an auxiliary Winding arranged in ac- With my invention, and Fig. .2 shows a diagram of the Connections of a machine of a type to which my invention is particularly applicable; r

In Fig. 1, A represents an armature-core which is built up of laminations in the usual manner. A represents the lltlllll armaturecoils, which are carried in the\slots and held regards reactance,

Schenectady, county l I the Wedges and above coils.

l l l three phase.

in place by retaining-Wedges N, of Wood or other suitable material. a represents an auxiliary Winding which is com osed of conducting-strips placed in the sots beneath the main armature In order to hold these strips se'cureh in place, the inner sides of the Wedges are slotted, as shown. These strips are placed in as many slots as necessary to give the desired voltage, and the strips are connected to give a winding of any desired character.

In Fig. 2 are shown the connections of a machine of the type described in my former patent above mentioned, to which the arraugemeut of the auxiliary Winding above described is particularly applicable. In this figure, A represents the main armature Winding, and a the auxiliary Winding. For the sake of simplicity both windings are shown as, Grannne-ring windings. F represents the field-Winding, ivith a rectifying-commutator C. This commutator is of the type disclosed in my former patent, comprising a polyphasc arrangement of brushes 5 b and segments of a length sub stantially equal to the distance between brushes.

As fully explained in my former patent, if a polyphasc voltage is impressed upon the brushes a rectified current will be delivered to the field-Winding. The arrangement of brushes shown is adapted for a threephase excitation, and the aux liary Winding a is consequently arranged apd connected in lies with the several phases of t e auxiliary windinggand across the teri'ninals'of these resistances are connected the secondaries of transformers T T, the primaries of which are in series with the main armature-Winding. hese transformers serve to impress across the terminals of the resistances r in series With the auxiliary Winding voltages corresponding. in amount and phase to the armatore-current. These 7 transformers are so connected to the resistances that the phase impressed across the terminals of the resistances r is ninety degrees from thc phase of the voltage of the auxiliary itinding whcn the load on the machine is n 'an inductive. This arrangement, as fuliy explained in my former patent, gives proper com ounding. for both ind which is provided Rcsistances 7' are laced in se uctive and n'on-induct1ve loads.

.wlinld ilizii'y \vim'ling which, performs the function I, carried inthc Slotsin said Wedges. bl Mm shunL-tmiisl'm'mei-s 15 so arranged as 1 With the :ii'mngcriimit as described above it will be soon that he expanse of employing SllU1!lj-ilzlhSYUIIIICTS in! supplying the shunt- OXC' lint-ion 1S Ollllllllzl'lfiftl, and the auxnni, in increase the of thonmchinc. Furthcinioi'c, the location of the auxiliary Winding such as to giw'rr it :1 minimum reactance, which is highly mlvnnmgonus as IQgitlda mmnmbulion.

f'fhzil l claim as new, and desire to secure i. in :L (.hYilRllHkOlOl'll'i( nmahino, a fieldiiiui'y -1 hiding being; coi'mpos-ed 0 condua:

all 3 I carried in the slots in said )1, 1 slutvLc-d zn'mnl'lire-(aura, :1. main IIIUIZL- strips carried beneath said retaining mzuis and above the main Minatum-Winding.

2. In a dynamo-electric machine, a slotted core, :1 11min Winding car'ried in said slots, r0- mining-weilges for said Winding; provided with slots ()1) their inner sidas, and an auX- ilim'y Winding comprising 00ndnoting-strips 3. in a dynam -electricmachine, 51, fie1dwinding provided with 1:, reclz liying-uomnmtutor, 2i slotted urinaltum-0on2, a, main armam- UUG"\\ill(.llil carried in said shots retaining-- WLdgOs for said arnml'wc-winding having slots on their inner sides, and an anx'iliaii'y Winding cnni'iectcd l4.) said illOl(l-Wil.](li1l2 through said cm'mnni/iihu', said auxiliary winding: being con'lposed 0i conducting-strips vxodgos.

In witness whm'eof I have hvi'euni'n ant my hand this 27th day of June, 1905.

lillh fi'l' i. W. "2hlliliillliliSUN.

BENJAMIN E. ii l'lnnn r; O RFOR n. 

